The creation of microelectronic devices typically requires the formation of traces or other features in the dielectric material (or another area) of a substrate. Laser projection patterning (LPP), which uses laser ablation to form such features, is one patterning technique that offers advantages for microelectronic applications. Many other patterning techniques also are used. After trenches and vias are ablated or otherwise formed in the dielectric material they must be filled with an electrically conductive material such as copper in order to create electrical interconnects in the substrate. Filling the trenches and vias using standard techniques that combine electroless and electrolytic plating processes requires some degree of overplating above the dielectric surface in order to ensure adequate filling of all traces, lands or planes, and vias on the substrate. The overplated electrically conductive material must then be removed from the substrate in order to electrically isolate the traces and vias from each other and from an integrated circuit.
The overplated material could be removed using chemical mechanical planarization (CMP), which is a standard process for removal of overplated copper in the silicon die fabrication process. However, the use of CMP for substrate manufacture is technically challenging due to manufacturing geometry and may cause problems, including scratching of the dielectric layer, which can create reliability concerns. In addition CMP is generally cost prohibitive in manufacturing organic substrates.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the discussion of the described embodiments of the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method. Furthermore, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or non-electrical manner. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. Occurrences of the phrase “in one embodiment” herein do not necessarily all refer to the same embodiment.